Cerebral palsy is movement and posture disorder, occurs because of nonprogressive damage in the brain before, during or after delivery of a child. CP children will be having difficulty in achieving their developmental milestone. Some of CP will present with compliance, personal, social and psychological, behavioral and sensory issues too.

As we mention that there is a brain damage in cerebral palsy, brain have control all over the body for eg moving the legs and arms, for seeing the things, smelling the things, hearing , experience of touch…etc. so depending of area of damage brain loose its control over that particular function of body. Primarily in cerebral palsy damage occurs in area of locomotion where the control of legs and arm is operated.
In normal human body when our bone grows (increase the height of person) our muscle will get stretch and lengthen automatically. In normal human being because of routine locomotion and activity of daily life our muscle will get at least minimum muscular strength to perform that particular activity. In cerebral palsy these scenario is not happening muscle are neither going to lengthen by themselves nor going to expose challenge which required to strengthen them.  So more or less cerebral palsy children required therapy till they achieve their skeletal maturity.

Absolutely yes, sooner is better. Because of neural plasticity, In early life human brain has maximum potential to grow and learn new things. So before learning wrong thing or learning things in atypical way because of damage, it is very crucial to expose brain the normal and typical way of leaning the things with help of therapy.

It is easier to write on blank paper then write on paper which is already full so if we want to write in full paper we have to erase the previous writing, so same way it is difficult to erase the previous wrong memory from brain. That why it is strongly recommended to have early intervention in developmental disorder condition like cerebral palsy, down syndrome, Autism etc

Although both types of therapy help kids improve the quality of their lives, there are differences. Physical therapy deals with the issues of pain, strength, joint range of motion, endurance, and gross motor functioning, whereas Occupational Therapy deals more with fine motor skills, visual-perceptual skills, cognitive skills, and sensory-processing disorders.

Attention Deficit Disorder describes a behavior of persistent inattention that is more common and severe than in typical children of the same level of development. Attention Deficit Disorder is now classified as a separate category from Attention Deficit Hyperactive Disorder because not all children with the disorder are hyperactive.

- Lacks attention to detail particularly in schoolwork.
- Trouble completing tasks, often shifts from one uncompleted task to another.
- Daydreamer does not follow instructions.
- Difficulty following conversations, frequently interrupts and/or loses interest of subject    midpoint.
- Trouble remembering what someone just told them. 
- Frequently losing or misplacing homework, schoolbooks or other items.
- Fidgeting and squirming or problems staying seated.
- Moving around constantly, often running or climbing inappropriately.
- Blurting out answers to questions without waiting to be called on.
- Difficulty with tasks that require taking turns.
- Inability to keep powerful emotions in check, resulting in angry outbursts or temper tantrums.

Autism is a spectrum of disorder and developmental disability that affects communication and social abilities of child. Children with autism typically have difficulty in both verbal and nonverbal communication. They may have a difficulty in relating to the outside world and may have unusual reactions to the people around them. Children with autism may demonstrate aggressive behavior that may cause injury to themselves or others. The disorder also may cause sensitivity to the senses of sight, hearing, touch, smell, and taste.
A learning disability is not a problem with intelligence, often the individual's IQ falls within the normal range. Children and adults with a learning disorder have trouble processing sensory information, which interferes in their daily activities at school and work. They see, hear and understand things differently. A child with a learning disability cannot try harder, pay closer attention, or improve motivation on their own, they need help to learn how to do those things.

Most children with Sensory Processing Disorder (SPD) are just as intelligent as their peers. Many are intellectually gifted. Their brains are simply wired differently. They need to be taught in ways that are adapted to how they process information, and they need leisure activities that suit their own sensory processing needs.

Once children with Sensory Processing Disorder have been accurately diagnosed, they benefit from a treatment program of occupational therapy (OT) with a sensory integration (SI) approach. When appropriate and applied by a well-trained clinician, listening therapy (such as Integrated Listening Systems) or other complementary therapies may be combined effectively with OT-SI.

Occupational therapy with a sensory integration approach typically takes place in a sensory-rich environment sometimes called the "OT gym." During OT sessions, the therapist guides the child through fun activities that are subtly structured so the child is constantly challenged but always successful.

The goal of Occupational Therapy is to foster appropriate responses to sensation in an active, meaningful, and fun way so the child is able to behave in a more functional manner. Over time, the appropriate responses generalize to the environment beyond the clinic including home, school, and the larger community. Effective occupational therapy thus enables children with SPD to take part in the normal activities of childhood, such as playing with friends, enjoying school, eating, dressing, and sleeping.

Ideally, occupational therapy for SPD is family-centered. Parents are involved and work with the therapist to learn more about their child's sensory challenges and methods for engaging in therapeutic activities (sometimes called a "sensory diet)" at home and elsewhere. The child's therapist may provide ideas to teachers and others outside the family who interact regularly with the child. Families have the opportunity to communicate their own priorities for treatment.

Treatment for Sensory Processing Disorder helps parents and others who live and work with sensational children to understand that Sensory Processing Disorder is real, even though it is "hidden." With this assurance, they become better advocates for their child at school and within the community.

If you asking 100% curable then we would say no. we cannot make a cerebral palsy kid "cosmetically" 100% correct like a atypical human being. Therapy can make them functionally able in near normal way or near atypical way. As we have mention above therapy helps in gaining functional level during first decade. In second decade as skeletal structure grows faster than routine age therapy maintains the gained improvement. And at last generally CP (not all) will have botox or final corrective surgical procedure around 12-15 years of age so soon after the surgical procedure a vigorous rehabilitation is proved as gold mine in developmental scenario.